As far as I see it there were no flip-flops Joe always reliably walks liberal party line. He talks a lot about different positions but by end of the dat he always ends up in the same place.
Right between talking and walking he makes his master act of hand-wringing, where he is an undefeated world champion, indeed. However, this act is getting long in the tooth and I hope soon American public would stop paying attention to anything he says.
For vouchers, against vouchers.......etc. etc. It's all old news.